The program of research proposed in this continuation proposal will employ multiple correlative immunocytochemical protocols to delineate the corticotropin-releasing-factor (CRF) neuronal systems of the central nervous system. CRF immunopositive neurons have been demonstrated to reside in the paraventricular nucleus (PVN) of the hypothalamus and a major fiber projection from these cells was traced to the perivascular contact zone of the median eminence (ME) and proximal neural stem. An analysis of the interrelationships between these neurons and other peptidergic, catecholaminergic and serotonergic neurons located within the PVN and ME is proposed. This program of research will confront such fundamental issues as: What are the termination patterns of GABA, opiomelanocortin and dopaminergic neurons within the PVN and their relationships to CRF neurons? Do synaptic interactions exists between CRF and magnocellular vasopressin and oxytocin producing neurons? Do CRF neurons communicate with thyrotropin-releasing hormone producing neurons? What is the topographical arrangement between these peptidergic and transmitter axons in the ME with reference to CRF terminals? Do CRF neurons receive indolaminergic innervation from the brainstem? Is there synaptic communication between neuropeptide Y containing terminals and CRF neurons in the PVN? Does the central cholinergic system directly effect the CRF system? Are suprachiasmatic afferents responsible for the circadian rhythm of CRF production? What is the effect of neonatal adrenalectomy and glucocortico-steroid treatment on the development of the CRF system? Are ependymal cells involved in the transport of intraventricularly administered CRF? Basic information gleaned from these studies will provide the foundation to the understanding of the brain-pituitary-adrenal axis and will also provide important knowledge about the underlying basis of many clinical endocrinopathies related to the function of this axis.